/Engine/Source/Runtime/InteractiveToolsFramework/Public/BaseGizmos/TransformProxy.h
This delegate is fired whenever the internal transform changes due to a pivot reposition, ie on AddComponent and when SetTransform is called with bSetPivotMode being true.
typedef TMulticastDelegate_TwoParams< void, [UTransformProxy](API\Runtime\InteractiveToolsFramework\BaseGizmos\UTransformProxy) *, FTransform > FOnPivotChanged